With high integration of LSIs, a circuit line width required for a semiconductor device has been made to be very small year by year. In order to form a desired circuit pattern in a semiconductor device, a method is used in which by using a reduction projection type exposure apparatus, a high-accuracy original pattern (a mask, or in particular, one used by a stepper or a scanner is also referred to as reticle) formed on a quartz is reduced and transferred onto a wafer. The high-accuracy original pattern is drawn by an electron beam drawing apparatus, that is, an electron beam lithography technique is used.
The electron beam drawing apparatus performs drawing by deflecting an electron beam with a deflector. Examples of a role of the beam deflection by the deflector include control of the shape or size of a beam shot, control of the position of the shot, and blanking of the beam. When the deflector is driven with an output voltage from a DAC (digital analog converter) amplifier, a settling time for the output voltage corresponding to the load of the deflector is required. If the settling time is insufficient, an error in a movement amount of the electron beam due to the deflection occurs, causing a decrease in the accuracy of drawing. On the other hand, if the settling time is excessively long, a throughput decreases. Thus, it is desirable to set a settling time as short as possible within a range where the accuracy of drawing does not decrease.
In the related art, while a settling time is changed, a beam is deflected in a single direction (e.g., a +X direction) to draw an evaluation pattern (including development) with respect to a mask for evaluation, the drawing position is measured by using a position measuring device, and a shortest settling time among settling times with which a deflection shift amount from a design coordinate falls within a certain range is determined as an optimum settling time. However, with increasing the accuracy of a circuit pattern and making the circuit pattern to be minute, in a measurement result of a deflection shift amount of a drawn position from a design coordinate, it is difficult to separate a shift amount depending on the settling time and a shift amount due to variation of dimension/position caused by a process, an measurement error (measurement variations) of a position measuring device, or the like.
As described above, in the related art, due to another error factor such as measurement variations of the position measuring device, it is not possible to accurately evaluate the deflection shift amount depending on the settling time, so that it is not possible to obtain an optimum settling time.